Pavel Machek [pavel@xxxxxx] wrote:
| Hi!
|
| > This gives a brief overview of the clone3() system call. We should
|
| Thanks!
|
| > eventually describe more details in existing clone(2) man page or in
| > a new man page.
|
| M. Kerrisk (see MAINTAINERS) maintains man pages...
Ok. I copied linux-api and M. Kerrisk is looking at this patchset.
|
| > Changelog[v8]:
| > - clone2() is already in use in IA64. Rename syscall to clone3()
| ...
| > Index: linux-2.6/Documentation/clone2
| > ===================================================================
| > --- /dev/null 1970-01-01 00:00:00.000000000 +0000
| > +++ linux-2.6/Documentation/clone2 2009-10-12 19:54:38.000000000 -0700
|
| clone3?
Ah, yes, will fix.
|
| > +struct clone_struct {
| > + u64 flags;
| > + u64 child_stack;
|
| u64 seems wrong on 32 bit platforms. ulong?
|
| > + u32 nr_pids;
|
| So nr_pids is either 1 or 2?
No. With pid namespaces, which can be nested to arbitrary levels, each
process has several pid numbers - one in its own namespace and one in
each ancestor pid namespaces.
nr_pids specifies the number of pids the user cares about. IOW, if you
checkpoint a process that is 3 levels below the init-pid-ns, and you
care about the pids for those three levels, you would pass in an
array of 4 pid_ts and nr_pids would be 4.
|
| > + u32 reserved1;
| > + u64 parent_tid;
| > + u64 child_tid;
| > + u64 reserved2;
| > +};
| > +
|
|
| > + See CLONE_NEWPID section of clone(2) man page for details about pid
| > + namespaces.
| > +
| > + The order pids in @pids corresponds to the nesting order of pid-
| > + namespaces, with @pids[0] corresponding to the init_pid_ns.
|
| Ok, so I'm confused.
Hope the above note on pid-namespaces helps, if not let me know.
|
| > + If a pid in the @pids list is 0, the kernel will assign the next
| > + available pid in the pid namespace, for the process.
| > +
| > + If a pid in the @pids list is non-zero, the kernel tries to assign
| > + the specified pid in that namespace. If that pid is already in use
| > + by another process, the system call fails with -EBUSY.
| ...
| > + On failure, clone3() returns -1 and sets 'errno' to one of following
| > + values (the child process is not created).
|
| Inconsistent with above. Syscalls really return -ERRCODE, errno is
| glibc magic.
Ok. Will make it consistent to say that it returns one of the error codes.
_______________________________________________
Containers mailing list
Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/containers
